1. Field of Invention
This invention relates to the convenient use of a fluid medication-filled cartridge inserted into a disposable cylindroid holder, such that the contents of the cartridge cannot become contaminated, while the user is protected from hollow-bore needle sticks. Such a device is sorely needed to protect users from hazardous needle sticks, and to protect patients from infectious disease hazards associated with the medical reuse of multiple dose vials, dental reuse of double-ended needles to empty more than one cartridge, and use of cylindrical containers whose leading caps are not sterile or tamper-proof. The device is especially designed toward preventing the transmission of HIV and HBV from patient to health care worker, from health care worker to patient and from patient to patient in health care settings.
2. Description of Prior Art
The use of disposable cylindric cartridges with reusable cylindric syringes having built-in plungers is customary in medical and dental practice. Being conical, lacking a built-in plunger and being disposable, the hollow cylindroid described here differs structurally from the prior syringe/cartridge art. The embodiment of one external trailing flange on the cylindroid is common in medical syringes, or two trailing flanges spaced a finger's breadth apart is common in dental syringes and in medical aspirating syringes designed for operation with one hand.
Means of hollow-bore steel needle attachment to the leading end of the hollow cylindroid or to the inserted pre-filled cartridge are well-known in the prior art. The dispensation of sterile cartridge in a three part puncture-resistant shielding system, the leading two parts of which are reused to protect the leading needle between uses, and before safe disposal was disclosed by Shields in U.S. Pat. No. 5,176,657 (01-05-93). The means of attaching a separate plunger to a fluid-filled cartridge is remindful of that in the Wyeth.TM. Tubex.RTM. system. However, the Tubex.RTM. system leaves the leading narrow end of the attached cartridge unprotected, is fragile and cannot be used inside the mouth. In the instant invention, wedge impaction of the leading shoulder of a cylindric gass cartridge in the leading conical bore of the hollow cylindroid not only avoids this problem, but also stabilizes the leading hollow-bore steel needle, prevents rotation of the cartridge when a separate plunger is reversibly attached to the trailing end of the cartridge piston and prevents the cartridge from falling out of the hollow cylindroid after use and safe disposal.
The separate reusable plunger is a versatile innovation, partly because it can be reused many times and partly because component parts are interchangeable, e.g. leading threaded receptacle, cork screw or harpoon; trailing thumb-ring or thumb-piece; and removable cap whose diameter can be varied. The sliding sleeve, however, must tightly fit the trailing bore of the hollow cylindroid in order to direct the thrust of the plunger and maintain stability of the entire; system, especially when used with a single hand.
The application of a needle which automatically recaps itself, cf. Kuracina et al in U.S. Pat. No. 4,998,933 issued 03/12/91, after use on the leading end of a cartridge or a syringe provides an alternative preferred embodiment, especially for medical, as opposed to dental usage.